1. Field of the Invention
This invention relates to a power-and-free conveyor, and more particularly to a device for stopping carriers and accumulating following carriers in a power-and-free conveyor of the type in which pushers attached to a drive chain on a power line engage with one of rear surface of covers mounted on trolleys of which a carrier on a free line is composed.
Throughout the specification and the appended claims, the terms "front" or "forward" and "rear" or "rearward" are based on the direction of travel of the conveyors. Thus, the former refers to the direction in which the conveyor advances and the latter to the opposite direction.
2. Description of the Prior Art (Prior Art Statement)
As disclosed in U.S. Pat. No. 3,906,864 and U.S. Pat. No. 4,038,925, a power-and-free conveyor of the type above mentioned is already known. The power-and-free conveyor includes a number of pusher dogs pivoted at their upper portion by pins on pusher dog supporting members attached to a drive chain on a power rail and engageable with a rear surface of a cover mounted on a front free trolley included in a carrier. The pusher dog supporting member is further provided with a stopper and other auxiliary members for holding the pusher dog in engagement with the front trolley to advance the carrier and cooperate with a cam member of a stop means disposed on the conveyor line to bring the carrier to a stop. The stopper stops the pusher dog in its vertical downwardly directed position where the pusher dog can engage with the trolley. When the carrier reaches the location where the carrier is to be stopped, a downwardly projecting member of the auxiliary members comes into contact with the cam which has already projected into the path of travel of the member. As a result of that the pusher dog is released from the stopper and is disengaged from the trolley. In this case, the pusher dog is released from the stopper by the medium of the auxiliary members including the downwardly projecting member, and the cam of the stop means has to project into the path of travel of the trolley.